Ball bearings wear less than brass or graphite bushings. That means that they don't develop the characteristic looseness or 'wobble' that bushings do after a year or so of heavy use. Of course, many anglers don't put that much 'mileage' on their reels, so the difference isn't that noticeable. Ball bearings are not necessarily smoother than bushings. When they are brand new, well made bushings can actually be *smoother* than ball bearings. Also, bushings require less 'break-in' time. That's why a brand-new Shimano Citica can actually feel smoother than a Curado, even though the Curado has many more ball bearings.

For normal baitcaster reels, like Shimano's, that have a 1-piece spool and axle, you have a bearing/bushing at 3 places on the spool shaft and 2 places on the crank shaft.

With the ABU-Garcia "Ultra-Cast" design (spool separate from the axle), you have 2 bearings/bushings on the spool, and 2 more on the crank shaft. Any more than that are superfluous, IMHO.

The roller bearing found in some reels is a special kind of roller bearing that only turns one way. It is what gives the reel the continuous anti-reverse feature. They put it on the crank shaft, under the handle and drag-star. As such, it takes the place of one of those locations I mentioned above.

Some reels also have a ball bearing right above the roller bearing on the same shaft. This helps to reduce the load on the roller bearing to assure that your anti-reverse doesn't crap out at the wrong time. You'll probably see less of this as the quality of the one-way roller bearings improves.

Ball bearings improve the life of a reel, but they are not the *most* important feature, IMHO. The features you should look for in a reel, in the order that they usually appear as the price goes up are:

All metal, aluminum spool.

All metal frame

One-piece, cast aluminum frame

Ball bearings

As an example of what I'm talking about, I offer the Shimano Calcutta, which only has 2 ball bearings, plus the one-way roller bearing, but is arguably the best freshwater baitcaster made.